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Biomedical subjects

A Thomas

Publications and source records attributed to A Thomas.

At least 379 records · Page 21Linked to original sources
PubMed1993

p53 gene mutation in B-cell chronic lymphocytic leukemia is associated with drug resistance and is independent of MDR1/MDR3 gene expression.

We studied 53 patients with B-cell chronic lymphocytic leukemia (B-CLL) and found mutations of the p53 gene in 15%. Patients with p53 gene mutations were found to have an aggressive form of B-CLL disease characterized by advanced Rai stage, rapid lymphocyte doubling time (LDT), and resistance to chemotherapy. While 27 of 29 treated patients (93%) without p53 mutations achieved a partial remission, only one of seven treated patients (14%) with p53 mutations achieved a partial remission (P = .00009). Adjusting for prognostic factors (age, sex, race, and Rai stage), patients with p53 gene mutations had a 13-fold greater risk of death than patients without p53 mutations (P = .013). In addition to examining the clinical relevance of p53 gene mutations in B-CLL, we investigated the possible role of p53 gene regulation in the expression of the multidrug resistance genes MDR1 and MDR3. We quantitated MDR1 and MDR3 mRNA expression by reverse transcription-polymerase chain reaction (RT-PCR). Expression of both the MDR1 and MDR3 genes was independent of p53 gene mutation or prior drug treatment, and did not predict for clinical response. Our findings indicate that p53 gene mutations in B-CLL are associated with a poor clinical outcome and may be a prognostic indicator for drug resistance.

Adult↗
PubMed1993

Computer simulations of the flexibility of a series of synthetic cyclic peptide analogues.

The flexibility of a series of cyclic peptides derived from the epitope of a snake toxin is investigated using computer simulation techniques. Molecular dynamics (MD) simulations and vibrational analyses are performed on chemically constrained peptides modeled on the parent protein loop. In the 50 ps MD simulations, large variations in the atomic fluctuations are seen between the peptides, and can be related to the nature of the chemical constraints present in the molecules. Normal mode analyses are performed on energy-minimized configurations derived from the dynamics trajectories. The atomic fluctuations calculated from the normal modes are about 30% of those of the molecular dynamics for the more flexible peptides and 70% for the more constrained molecules. The calculated differences in flexibility between the molecules are much less significant in the harmonic approximation.

Amino Acid Sequence↗
PubMed1993

Management of synergistic bacterial gangrene in severely immunocompromised patients. Report of four cases.

We present four cases of perianal synergistic gangrene in severely immunocompromised patients. In all patients, gangrene was controlled by radical surgery, including defunctioning colostomy in three patients, backed up by appropriate antibiotic therapy. Three of the patients survived and left the hospital; the fourth died in the intensive care unit of overwhelming sepsis from an unidentified source other than the anus. We review the literature and conclude that such infections in these patients are not inevitably fatal and that radical surgery can result in a cure.

Adult↗
PubMed1993

Transducer related Enterobacter cloacae sepsis in post-operative cardiothoracic patients.

The use of intra-arterial pressure monitoring devices in patients undergoing major cardiac surgery is on the increase. Here we document an outbreak of Enterobacter cloacae septicaemia among seven post-operative cardiothoracic patients. Detailed investigations revealed the source of this nosocomial problem to be contaminated transducer heads. The need to follow strict aseptic measures in handling intra-arterial devices is emphasized, in order to minimize the morbidity and mortality in otherwise low-risk post-operative patients.

Cardiac Surgical Procedures↗
PubMed1993

Properties of Vero cytotoxin-producing Escherichia coli isolated from human and non-human sources.

Vero cytotoxin-producing Escherichia coli (VTEC) are an important cause of disease in man and animals. In addition to the production of VT these strains may possess other properties that are required for full virulence. Examples of some recent molecular studies are reviewed. Use of oligonucleotide probes and the polymerase chain reaction provide methods for the identification and typing of different VT genes. Several VTEC have the ability to cause attaching and effacing lesions of the epithelial microvilli. Hybridization experiments with the eae probe (E. coli attaching and effacing) showed homology with VTEC of human origin of eight different O serogroups. Properties of VTEC from human infections have been compared to strains isolated from animals and foods.

Animals↗
PubMed1993

Phage typing of Vero cytotoxin-producing Escherichia coli O 157 isolated in the United Kingdom: 1989-91.

Between 1989 and 1991 a total of 1092 Vero cytotoxin-producing Escherichia coli O 157 isolated in the United Kingdom were phage typed in the Laboratory of Enteric Pathogens (LEP). Twenty-three phage types was identified, the most frequent being types 2 (36.1%), 49 (29.6%), 1 (10.3%) and 4 (8.9%). Although isolations of O 157 VTEC have increased each year from 1 in 1982 to 532 in 1991, the predominant phage types have remained unchanged although the proportion of strains belonging to types 2 and 49 has increased. O 157 VTEC from 17 outbreaks were phage typed during this period with phage type 49 predominating (7 of 17 outbreaks).

Bacterial Toxins↗
PubMed1993

Vero cytotoxin-producing Escherichia coli, particularly serogroup O 157, associated with human infections in the United Kingdom: 1989-91.

This survey reports the results of investigations performed by the Laboratory of Enteric Pathogens (LEP), to identify evidence of human infection with Vero cytotoxin-producing Escherichia coli (VTEC) in the UK during the period 1989-91. Bacterial isolates, faecal specimens and serum samples were received from patients suffering from diarrhoea, bloody diarrhoea and haemolytic uraemic syndrome. Using serotyping, Vero cytotoxin gene probing and an ELISA for serum antibodies to E. coli O 157, evidence of infection was detected in 232, 428 and 615 individuals in 1989, 1990 and 1991 respectively. Of these individuals, 15% were reported as having HUS. Vero cytotoxin-producing E. coli O 157 was the most frequently encountered serogroup, with isolations from a total of 1092 individuals over the 3-year period. The incidence of VTEC infection increased from 0.41/100,000 in 1989 to 1.07/100,000 in 1991. The area with the highest rate of infection in each year was Scotland, increasing from 1.37/100,000 in 1989 to 3.97/100,000 in 1991.

Adolescent↗
PubMed1993

The influence of wages and house prices on British interregional migration decisions.

The factors affecting choice of destination of U.K. internal migrants are analyzed using Labour Force Survey data. "A logit analysis of destination choice indicates that job movers are attracted to areas with high wages but are not affected by high house prices in such areas. In contrast, active non-job movers are deterred from areas of high house prices. Regional house price differences do not influence the destination choice of homemakers or the terminally sick but they do influence the destination choice of retirees. All groups prefer to travel the least distance when moving."

Demography↗
PubMed1993

A class of perfect graphs in genetics.

A straightforward graphical representation of a genealogy is regularized by chording cycles using only male-female links. The resulting graph is shown to be perfect.

Female↗
PubMed1993

Clinical results with nonthoracotomy ICD systems.

The results of two separate US Food and Drug Administration clinical trials that involved endocardial and epicardial leads were compared with regard to patient demographics, detection and conversion characteristics, and subsequent clinical course including long-term survival experience. The patient groups, although not strictly contemporaneous, were sufficiently similar to allow meaningful comparisons. There were no significant differences in detection of induced arrhythmias and ability to convert them. The surgical mortality, infection rate, and incidence of other morbid complications were lower in patients who had received endocardial leads; however, the differences did not reach statistical significance. Survivals through 1 year of follow-up were uniformly high. These results suggest that the performance of the endocardial lead system is comparable to existing epicardial leads in similar patient populations.

Actuarial Analysis↗
PubMed1993

Use of digoxigenin-labelled oligonucleotide DNA probes for VT2 and VT2 human variant genes to differentiate Vero cytotoxin-producing Escherichia coli strains of serogroup O157.

Digoxigenin-labelled oligonucleotide DNA probes specific for B-subunit genes of Vero cytotoxin 2 (VT2) and a variant of VT2 (VT2vha) were used to differentiate 116 strains of Escherichia coli serogroup O157 belonging to phage types 1, 2, 4, 8, 14, and 49. Of these strains, 38% had sequences for both VT2 and VT2vha, 38% had sequences for VT2 only, and 24% had sequences for VT2vha only. Oligonucleotide probe hybridization subdivided strains of all of the phage types except phage type 1. The greatest variation in toxin gene pattern was observed with strains of phage type 14, for which there were six distinct patterns when the presence or absence of VT1 genes was also considered. Two strains from each phage type group were examined for bacteriophages encoding VT production. Two of the six VT2vha-producing strains carried phage from which DNA hybridized with the VT2vha-specific probe. Phages were not detected in the remaining four VT2vha strains, suggesting that genes may be chromosomally located or associated with a defective prophage. In contrast, seven of the eight VT2 strains carried phages from which DNA hybridized with the VT2-specific probe. Two strains of E32511 (O157:H-) were also investigated. One strain (E32511A) possessed gene sequences for both VT2 and VTvha and was shown to carry phage possessing gene sequences for VT2. With strain E32511B, however, phages were not detected and DNA hybridized only with the VT2vha probe. Analysis of total genomic DNA digested with restriction endonuclease EcoRI showed that polymorphisms were seen with VT2 strains and not with VT2vha strains.

Bacterial Toxins↗
PubMed1993

Volunteer hospice offers unique & special services.

Two types of hospices exist: medical and volunteer. Medical hospices are constrained by Medicare regulations. Volunteer hospices fill in the gaps that those regulations leave, providing flexible, supportive care. The community that is served by both medical and volunteer hospice programs offers truly comprehensive care to the dying and their families.

Hospices↗
PubMed1993

Updated care guidelines for patients with automatic implantable cardioverter defibrillators.

Since its clinical introduction, AICD therapy has gained significant acceptance. Some physicians consider it the "gold standard" in treating malignant tachyarrhythmias associated with sudden cardiac death. As the technology and therapy application have grown, nursing responsibilities have evolved as well. And, with the forthcoming combinations of technology such as AICDs with antitachycardia pacing and bradycardia pacing, the sophistication of the therapy is expected to increase. However, the most critical role for nurses in AICD patient care remains education. Increased utilization has made AICD implants more common, but many patients still lack the initial information and acceptance needed for therapeutic success. Health-care professionals who continue to update and share their understanding of this life-saving technology make invaluable contributions to the care of these patients who have received a second chance at life.

Defibrillators, Implantable↗
PubMed1993

A study of the consequences of malarial infection in pregnant women and their infants.

An outline is given of a field research study to be undertaken in Malawi to investigate the pattern and consequences of malaria in pregnancy and infants. The central question to be investigated is whether babies born to anaemic mothers in malarious areas are at increased risk of developing anaemia or altered risk for morbidity from malaria or develop anaemia in the first year of life. The framework for the case control and cohort study to be undertaken is outlined.

Anemia↗
PubMed1993

[The circadian rhythm of ciliary beat frequency of human nasal cilia in probands with healthy lungs and in patients with chronic obstructive lung disease. Includes adrenergic stimulation by terbutaline].

Brush biopsies taken from the human nose eight times during 24 hours were examined under a phase contrast microscope and the ciliary beat frequency was measured directly by a photosensitive cell. Ten healthy volunteers showed in two series of measurements, at 600, 1200, 1800, 2400 initially and 300, 900, 1500, 2100 six weeks later, a marked decrease in ciliary beat frequency towards the middle of the day and a statistically higher beat frequency in the early morning. The influence of the adrenergic drug terbutaline led to a cilioexcitation ranging from 0.1-1.4 Hz (mean: 0.9 Hz). In contrast to, neither a circadian variation of the ciliary beat frequency nor a stimulation by terbutaline could be observed in a group of fifteen patients with chronic bronchitis or bronchiectasis at 600, 1200, 1800 and 2400.

Adult↗